We're beginning to test KVM a bit here to compare it to XS, but I was curious if there were reasons that you all aware of to choose one over the other.
]]>https://mangolassi.it/topic/13907/kvm-vs-xenserverRSS for NodeTue, 20 Mar 2018 02:12:13 GMTFri, 02 Jun 2017 14:28:53 GMT60We're beginning to test KVM a bit here to compare it to XS, but I was curious if there were reasons that you all aware of to choose one over the other.
]]>https://mangolassi.it/post/303759https://mangolassi.it/post/303759Invalid DateWell, flexibility is a big one. KVM is just the hypervisor itself, so you are building out your own ecosystem choices. XS is the stack, so you are limited to the choices in that stack. XS is good and has a lot of good things baked in and some good add ons, added on but it also removes some flexibility, makes some dumb choices and slows down development (compared to straight Xen.)

KVM is definitely getting way more attention and is gaining on Xen all of the time. Xen has some cool tech coming down the pike that will potentially leapfrog it over KVM in terms of Linux virtualization performance, but right now KVM has the lead in a small way with Linux and a large way with Windows where KVM has always focused.

Well, flexibility is a big one. KVM is just the hypervisor itself, so you are building out your own ecosystem choices. XS is the stack, so you are limited to the choices in that stack. XS is good and has a lot of good things baked in and some good add ons, added on but it also removes some flexibility, makes some dumb choices and slows down development (compared to straight Xen.)

KVM is definitely getting way more attention and is gaining on Xen all of the time. Xen has some cool tech coming down the pike that will potentially leapfrog it over KVM in terms of Linux virtualization performance, but right now KVM has the lead in a small way with Linux and a large way with Windows where KVM has always focused.

So in performance they have rough parity with Linux workloads, and KVM currently has the edge in Windows? It seems odd to me that KVM has focused on Windows. I would've thought the other way around.

Well, flexibility is a big one. KVM is just the hypervisor itself, so you are building out your own ecosystem choices. XS is the stack, so you are limited to the choices in that stack. XS is good and has a lot of good things baked in and some good add ons, added on but it also removes some flexibility, makes some dumb choices and slows down development (compared to straight Xen.)

KVM is definitely getting way more attention and is gaining on Xen all of the time. Xen has some cool tech coming down the pike that will potentially leapfrog it over KVM in terms of Linux virtualization performance, but right now KVM has the lead in a small way with Linux and a large way with Windows where KVM has always focused.

So in performance they have rough parity with Linux workloads, and KVM currently has the edge in Windows? It seems odd to me that KVM has focused on Windows. I would've thought the other way around.

Basically Xen owned the Linux performance space by doing PV so KVM would have to have reinvented the wheel just to compete, but they were able to go after non-PV workloads (like Windows) pretty heavily to differentiate themselves. So mostly just market pressure.

Well, flexibility is a big one. KVM is just the hypervisor itself, so you are building out your own ecosystem choices. XS is the stack, so you are limited to the choices in that stack. XS is good and has a lot of good things baked in and some good add ons, added on but it also removes some flexibility, makes some dumb choices and slows down development (compared to straight Xen.)

KVM is definitely getting way more attention and is gaining on Xen all of the time. Xen has some cool tech coming down the pike that will potentially leapfrog it over KVM in terms of Linux virtualization performance, but right now KVM has the lead in a small way with Linux and a large way with Windows where KVM has always focused.

So in performance they have rough parity with Linux workloads, and KVM currently has the edge in Windows? It seems odd to me that KVM has focused on Windows. I would've thought the other way around.

Basically Xen owned the Linux performance space by doing PV so KVM would have to have reinvented the wheel just to compete, but they were able to go after non-PV workloads (like Windows) pretty heavily to differentiate themselves. So mostly just market pressure.

How much of a Linux performance difference nowadays between Xen and KVM? Boot up time, IOPS, etc...

Well, flexibility is a big one. KVM is just the hypervisor itself, so you are building out your own ecosystem choices. XS is the stack, so you are limited to the choices in that stack. XS is good and has a lot of good things baked in and some good add ons, added on but it also removes some flexibility, makes some dumb choices and slows down development (compared to straight Xen.)

KVM is definitely getting way more attention and is gaining on Xen all of the time. Xen has some cool tech coming down the pike that will potentially leapfrog it over KVM in terms of Linux virtualization performance, but right now KVM has the lead in a small way with Linux and a large way with Windows where KVM has always focused.

So in performance they have rough parity with Linux workloads, and KVM currently has the edge in Windows? It seems odd to me that KVM has focused on Windows. I would've thought the other way around.

Basically Xen owned the Linux performance space by doing PV so KVM would have to have reinvented the wheel just to compete, but they were able to go after non-PV workloads (like Windows) pretty heavily to differentiate themselves. So mostly just market pressure.

How much of a Linux performance difference nowadays between Xen and KVM? Boot up time, IOPS, etc...

KVM has a slight edge right now. But it is expected to be lost in the future.

Well, flexibility is a big one. KVM is just the hypervisor itself, so you are building out your own ecosystem choices. XS is the stack, so you are limited to the choices in that stack. XS is good and has a lot of good things baked in and some good add ons, added on but it also removes some flexibility, makes some dumb choices and slows down development (compared to straight Xen.)

KVM is definitely getting way more attention and is gaining on Xen all of the time. Xen has some cool tech coming down the pike that will potentially leapfrog it over KVM in terms of Linux virtualization performance, but right now KVM has the lead in a small way with Linux and a large way with Windows where KVM has always focused.

So in performance they have rough parity with Linux workloads, and KVM currently has the edge in Windows? It seems odd to me that KVM has focused on Windows. I would've thought the other way around.

Basically Xen owned the Linux performance space by doing PV so KVM would have to have reinvented the wheel just to compete, but they were able to go after non-PV workloads (like Windows) pretty heavily to differentiate themselves. So mostly just market pressure.

How much of a Linux performance difference nowadays between Xen and KVM? Boot up time, IOPS, etc...

KVM has a slight edge right now. But it is expected to be lost in the future.

Well, flexibility is a big one. KVM is just the hypervisor itself, so you are building out your own ecosystem choices. XS is the stack, so you are limited to the choices in that stack. XS is good and has a lot of good things baked in and some good add ons, added on but it also removes some flexibility, makes some dumb choices and slows down development (compared to straight Xen.)

KVM is definitely getting way more attention and is gaining on Xen all of the time. Xen has some cool tech coming down the pike that will potentially leapfrog it over KVM in terms of Linux virtualization performance, but right now KVM has the lead in a small way with Linux and a large way with Windows where KVM has always focused.

So in performance they have rough parity with Linux workloads, and KVM currently has the edge in Windows? It seems odd to me that KVM has focused on Windows. I would've thought the other way around.

Basically Xen owned the Linux performance space by doing PV so KVM would have to have reinvented the wheel just to compete, but they were able to go after non-PV workloads (like Windows) pretty heavily to differentiate themselves. So mostly just market pressure.

How much of a Linux performance difference nowadays between Xen and KVM? Boot up time, IOPS, etc...

KVM has a slight edge right now. But it is expected to be lost in the future.

Lost in the future from XenServer or Xen or Both?

Xen for sure. XenServer famously strips the power of Xen out, so who knows.

]]>https://mangolassi.it/post/303982https://mangolassi.it/post/303982Invalid DateLike XenServer removed support for DRBD and Fault Tolernace. Argh
]]>https://mangolassi.it/post/303983https://mangolassi.it/post/303983Invalid DateIt's expected that the next incarnation of Xen will use the PVH2 virtualization mode with Linux guests, bringing back some of the PV advantage.
XenServer is pretty limited but the XAPI are solid.

KVM performs very well, has less hardware limitations than XS and can be used on any Linux installation without fancy modding.
Plain Xen is much harder than both XS and KVM of course, many stuff like VGA passthrough of the dom0 and networking are completely up to the user.

The libvirt stack (that can be used with both KVM and plain Xen) is very mature and has plenty of features. I really like the automatic installation of the guests (virt-builder) and the various guest os inspection tools.

The setup is complicated (on purpose?) and the interface is no that great, but it works. My last experience with oVirt was in 2016/03, maybe now could be much better. But a great cli cannot be beaten…
IMHO most of the people think they need a gui control panel because of the "VMware cult": nice GUI client, cumbersome CLI.
PowerCLI is usable, but not for interactive use. Virsh (for KVM) is simply great.

How come there is nothing like ProxMox or XOA for KVM?
I guess ProxMox is KVM!

Scale? Nutanix?

KVM has loads of them. Just approached in a different way.

With this solutions you throw away some of the main advantages of KVM:

Completely FLOSS. No license issue in any way, no cost, ever. As many spare hosts as you want;

Every feature of the hypervisor is exploitable;

It's not dependent on a particular distro, vendor, product;

It's a core project developed by the biggest player in the OSS space, so no risk of abandonment, very high quality of the code etc.

]]>https://mangolassi.it/post/304043https://mangolassi.it/post/304043Invalid DateI think that the only thing I truly miss in KVM is not a fancy GUI, but instead a stateless host OS 'a la XenServer/ESXi' that I can safely deploy to a usb drive. Something like CentOS atomic host should be good, but focused on KVM instead of Docker.
]]>https://mangolassi.it/post/304047https://mangolassi.it/post/304047Invalid Date@black3dynamite said in KVM vs XenServer:

I think that the only thing I truly miss in KVM is not a fancy GUI, but instead a stateless host OS 'a la XenServer/ESXi' that I can safely deploy to a usb drive. Something like CentOS atomic host should be good, but focused on KVM instead of Docker.

You should be able to do a USB install and ship the logs off to somewhere else. Then just mount your disks/volume for the guests.